Heretofore, when a high boiling compound containing sublimable materials as impurities is distilled and purified, there exist a possibility that the sublimable materials block a pipe by subliming and a problem that solid sublimable materials adhered to the pipe dissolves in a high boiling compound to be distilled out, thereby inhibiting an increase in purity of the high boiling compound. Thus, it has been difficult to distill and purify a high boiling compound containing sublimable materials as impurities.
Meanwhile, demand for products of higher purity has been increasing every year. In particular, a reduction in metal components of a product used in a semiconductor production process is strongly demanded. As a purification method which can remove such metal components efficiently, purification by distillation is suitable.
In recent years, it has been reported that alkyladamantyl(meth)acrylate polymers have high dry etching resistance in a semiconductor production process (refer to JP-A 5-265212), and a possibility of their use as a resist material for a semiconductor has been receiving attention. In the case of these alkyladamantyl(meth)acrylates as well, those having reduced metal components and high purity are desired for use as a resist material for a semiconductor.
It is known that the alkyladamantyl(meth)acrylate can be generally produced by obtaining adamantanone first and then alkyladamantanol from adamantane as a raw material and then reacting the alkyladamantanol with (meth)acrylic acid, (meth)acrylate, (meth)acrylic anhydride or a (meth)acrylic acid halide. However, since the alkyladamantyl(meth)acrylate which is a target compound is a high boiling compound and adamantane, adamantanone and alkyladamantanol remaining as an unreacted raw material and reaction byproducts are sublimable materials having a sublimation starting temperature (sublimation point) lower than a boiling point of the target compound, it has been difficult to purify the target compound efficiently by distillation.
It is an object of the present invention to provide a method for producing a target compound of high purity by applying an efficient purification method to a crude organic compound containing sublimable materials as impurities for which an efficient distillation/purification method has not been known.
The present inventor has made intensive studies to solve the above problem. As a result, he has found that a target organic compound can be efficiently purified by distilling a crude organic compound in the presence of a compound having a boiling point lower than that of the target organic compound. The present invention has been completed by the finding.